Optimization and Validation of Electric Acoustic Stimulation (EAS) Mapping as a Function of Residual Hearing After CI-Implantation

April 23, 2026 updated by: Armina Kreuzer, Luzerner Kantonsspital
The aim of this clinical study is to investigate how the fitting of an EAS (electrical acoustic stimulation) based on electrocochleography (ECochG) thresholds compares to fitting based on pure tone audiogram thresholds in terms of speech intelligibility in quiet and noise. The personal feedback from the study participants regarding the question of better fitting and the resulting sound quality should also be included in the analysis.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

As the indications for Cochlear Implant (CI) Surgery expand to also include hearing impaired patients with some residual hearing in the ipsilateral (to be implanted) ear, residual hearing preservation during the surgical intervention becomes even more important. It is also known from the literature that patients will benefit from having good residual acoustic hearing after CI-Implantation in terms of the sound quality. This is particularly so for speech comprehension in noise as well as for music perception with the CI.

Present-day clinical Sound Processor programming software provides Electric Acoustic Stimulation (EAS) to account for preserved residual hearing. For an optimized EAS fitting, it is postulated here that optimal conditions are achieved when the electric and acoustic stimulation do not overlap. To achieve this, the acoustic stimulation ought to be limited to only regions where there is still useful acoustic hearing, while the electric stimulation should also be restricted to regions where there is no longer significant useful acoustic hearing. In the Maestro clinical software, the threshold for significant useful acoustic hearing is set to 65 dB Hearing Level (HL). This then determines the cut-off frequency between the acoustic and electric stimulation regions.

The standard clinical Maestro software computes this cut-off based on a regular pure tone audiogram (PTA) which has been manually stored in the software. However, it is arguable that this does not always represent an accurate cut-off frequency required for optimal fitting because the audiogram thresholds themselves are subjective in nature and can often vary in a test-retest situation, depending on the attention and reaction times of the patient. It has been reported that the unaided thresholds do not play a significant role in the EAS fitting. In this respect, it may be more accurate and beneficial to use objective measures such as electrocochleography (ECochG) to determine the thresholds of the residual hearing.

The current family of Med-El Cochlear Implants are equipped with the capability to perform ECochG measurements using the implant's own intracochlear electrodes within the scala tympani. The measurements can also be conducted intraoperatively or postoperatively. This intracochlear ECochG feature of the implants therefore allows us to objectively determine the residual hearing thresholds.

The aim of this study is to discuss the advantages of objective fitting of the EAS compared to subjective fitting using a PTA with respect to speech intelligibility in quiet and in noise. The personal feedback from the study participants regarding the question of better fitting and the resulting sound quality should also be included in the analysis.

From the existing literature, it is not expected that there should be any significant gender effects. This also does not belong to the primary aims of this study and we will not be investigating this aspect.

Study Type

Interventional

Enrollment (Estimated)

12

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Patients aged between 18-85 years.
  2. Cochlear Implant (CI) candidates with measurable post-operative low-frequency residual hearing (125Hz <65dB, 250Hz <65dB, 500Hz <65dB).
  3. Only patients with MED-EL EAS.
  4. Written informed consent must be obtained prior to study start.

Exclusion Criteria:

  1. Patients with cognitive impairments who, as a result, lack the capacity to make decisions.
  2. Uncooperative patients regarding pure tone audiometry thresholds measurements.
  3. Morbus Menière or intracochlear/ vestibular schwannoma

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: Sequence A, subjective followed by objective fitting
In this sequence, the EAS is fitted in the first three months (period 1) using the subjective fitting method based on the thresholds in the pure tone audiogram. This is followed by three months (period 2) fitting using the objective fitting method based on the thresholds from electrocochleography.
Other: The objective fitting method of the EAS based on the thresholds of electrocochleography is the intervention of our study.
Measured ECochG thresholds will be used in the initial EAS fitting in period 1 for sequence B. For sequence A, the ECochG-based EAS fitting (with up-to-date ECochG thresholds) will take place three months later at the beginning of period 2.
Other: The subjective adjustment of an EAS based on thresholds from the pure tone audiogram.
The control intervention is the subjective EAS fitting based on PTAs. This is provided to sequence A at the beginning of period 1 baseline and to sequence B at the beginning of period 2.
Other: Sequence B, objective followed by subjective fitting
In this sequence, the EAS is fitted in the first three months (period 1) using the objective fitting method based on the thresholds from electrocochleography. This is followed by three months (period 2) fitting using the subjective fitting method based on the thresholds in the pure tone audiogram.
Other: The objective fitting method of the EAS based on the thresholds of electrocochleography is the intervention of our study.
Measured ECochG thresholds will be used in the initial EAS fitting in period 1 for sequence B. For sequence A, the ECochG-based EAS fitting (with up-to-date ECochG thresholds) will take place three months later at the beginning of period 2.
Other: The subjective adjustment of an EAS based on thresholds from the pure tone audiogram.
The control intervention is the subjective EAS fitting based on PTAs. This is provided to sequence A at the beginning of period 1 baseline and to sequence B at the beginning of period 2.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Speech Recognition Threshold (SRT50)
Time Frame: Three months after EAS fitting

The primary outcome measure is the Speech Recognition Threshold (SRT50) at three months after EAS fitting (either objective or subjective EAS fitting in a cross-over design).

The SRT50 measures speech understanding in noise and is defined as the Signal-to-Noise Ratio (measured in dB SNR) which yields 50% speech understanding, as determined by the OLSA test.
Three months after EAS fitting

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Subjective level of auditory benefit
Time Frame: Three months after EAS fitting
A secondary outcome measure is subjective level of auditory benefit at three months after EAS fitting (either objective or subjective EAS fitting in a cross-over design), as determined using the HISQUI-19 (Hearing Implant Sound Quality Index) questionnaire.
Three months after EAS fitting
Subjectively preferred EAS fitting method
Time Frame: at the end of the study, six months after baseline
The subjectively preferred EAS fitting method at the end of the study will be examined.
at the end of the study, six months after baseline
Post-operative ECochG and PTA tresholds
Time Frame: Three months after EAS fitting (either objective or subjective EAS fitting)
Post-operative ECochG and PTA thresholds at three months after EAS fitting (either objective or subjective EAS fitting in a cross-over design).
Three months after EAS fitting (either objective or subjective EAS fitting)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Luzerner Kantonsspital

Collaborators

MED-EL Elektromedizinische Geräte GesmbH

Investigators

  • Principal Investigator: Armina Kreuzer, Dr., Luzerner Kantonsspital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

May 1, 2026

Primary Completion (Estimated)

November 1, 2027

Study Completion (Estimated)

November 1, 2027

Study Registration Dates

First Submitted

March 12, 2026

First Submitted That Met QC Criteria

March 12, 2026

First Posted (Actual)

March 17, 2026

Study Record Updates

Last Update Posted (Actual)

April 24, 2026

Last Update Submitted That Met QC Criteria

April 23, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • EAS_fitting

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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